While out on a run recently, I passed a hiker on the trail. “My knees hurt just watching you,” he told me, shaking his head. It was a variation on a comment I hear over and over: Keep running like that, and you’ll give yourself arthritic knees.
The notion that running causes wear and tear on the joints that could spur arthritis makes some intuitive sense. But is it true?
No — if anything, running probably offers protection from osteoarthritis, says Paul Williams, an exercise scientist at Lawrence Berkeley National Laboratory who leads the National Runners’ Health Study and the National Walkers’ Health Study. These projects have enlisted almost 90,000 runners and walkers and followed them since the studies began, in 1991 and 1997, respectively. In an analysis recently published in the journal Medicine & Science in Sports & Exercise, Williams calculated rates of osteoarthritis and hip replacement among participants in his studies and found that runners were approximately half as likely as walkers to develop osteoarthritis or need a hip replacement. Runners who ran the most had the lowest risk.
The notion that running causes osteoarthritis arises from a misperception about how joints work, says Alex Hutchinson, a science journalist who is the author of the Sweat Science blog at Runner’s World and the book “Which Comes First, Cardio or Weights? Fitness Myths, Training Truths, and Other Surprising Discoveries from the Science of Exercise.” “People think the joint is just a static, inert hinge that wears down, but it’s actually a dynamic, living thing that can respond to stress and adapt and get stronger,” he says. Rather than wear down cartilage and other joint tissue, running appears to strengthen them, Hutchinson says.
The latest research shows that osteoarthritis isn’t just a result of wear and tear on your joints, says Patience White, vice president for public health policy and advocacy at the Arthritis Foundation. Instead, the disease arises from an interplay between environment and genetics. The strongest risk factors for osteoarthritis are obesity and family history, says White, who is also a professor of medicine and pediatrics at the George Washington University School of Medicine and Health Sciences.
Every extra pound you carry is akin to four pounds on your knees, White says: “If you lose five pounds, that’s like 20 pounds across your knees.”